“Much like classic buffer overflows, speculative out-of-bounds stores can modify data and code pointers. Data-value attacks can bypass some Spectre-v1 mitigations, either directly or by redirecting control flow. Control-flow attacks enable arbitrary speculative code execution, which can bypass fence instructions and all other software mitigations for previous speculative-execution attacks. It is easy to construct return-oriented-programming (ROP) gadgets that can be used to build alternative attack payloads,” they added.

Spectre 1.2 impacts CPUs that fail to enforce read/write protections, allowing an attacker to overwrite read-only data and code pointers in an effort to breach sandboxes, the experts said.

Both Intel and ARM have published whitepapers describing the new vulnerabilities. AMD has yet to make any comments regarding Spectre 1.1 and Spectre 1.2.

“We are not currently aware of any instances of BCBS in our software, but we are continuing to research this vulnerability class and will work with industry partners to release mitigations as required,” the company said.

Oracle is also assessing the impact of these vulnerabilities on its products and has promised to provide technical mitigations.

“Note that many industry experts anticipate that a number of new variants of exploits leveraging these known flaws in modern processor designs will continue to be disclosed for the foreseeable future,” noted Eric Maurice, Director of Security Assurance at Oracle. “These issues are likely to primarily impact operating systems and virtualization platforms, and may require software update, microcode update, or both. Fortunately, the conditions of exploitation for these issues remain similar: malicious exploitation requires the attackers to first obtain the privileges required to install and execute malicious code against the targeted systems.”

Just as the researchers published their paper, Intel made a $100,000 payment to Kiriansky via the company’s HackerOne bug bounty program. The experts did reveal in their paper that the research was partially sponsored by Intel.

Following the disclosure of the Spectre and Meltdown vulnerabilities in January, Intel announced a bug bounty program for side-channel exploits with rewards of up to $250,000 for issues similar to Meltdown and Spectre. The reward for flaws classified “high severity” can be as high as $100,000.

Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.